Groups which has been created in the event to identify a particular set of attendees/users can be deleted if required.
How to delete a group
Click on the "People" tab in the admin panel of the event
Click "Groups"
Select the group that you want to delete from the event
Once selected the required group click on the "Delete" option
It will then show you this view
Default groups are locked. They cannot be deleted, merged, or changed in their attendance type.
